<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #btn{
            display: block;
            margin: 0 auto;
            width: 100px;
            height: 50px;
            background: aqua;
            border: 0;
            border-radius: 15px 0;
            position: relative;
            transform: skewX(-20deg);
        }
        span{
            display: inline-block;
            transform: skewX(20deg);
        }
        #btn:before, #btn:after{
            content: '';
            height: 20px;
            width: 20px;
            position: absolute;
        }
        #btn:before{
            bottom: 0;
            left: -20px;
            background: radial-gradient(
                    circle at 0 0,
                    transparent 20px,
                    aqua 21px
            );
        }
        #btn:after{
            top: 0;
            right: -20px;
            background: radial-gradient(
                    circle at 100% 100%,
                    transparent 20px,
                    aqua 21px
            );
        }
    </style>
</head>
<body>
    <button id="btn">
        <span>倾斜按钮</span>
    </button>
</body>
</html>